Telephone-exchange system



H. G. WEBSTER TELEPHONE EXCHANGE SYSTEM Original Filed June '10, 1907 4 Sheets-Shut 1 gli v'f 1112*).

' H. G. WEBSTER TELEPHONE EXCHANGE SYSTEM Original Filed June l()y 1907 4 Sheets-Shut 2 H. G. WEBSTER TELEPHONE EXCHANGE SYSTEM Original Filed June 1o, 190V '4 Sheds-Shui 5 H. G. WEBSTER TELEPHONE EXCHANGE sYsTEu- Original Filed June 10, 190'? 4\Sheets-Shot 4 Patented Oct. 27, 1925.

UNITED -STA 'rss PATENT oF'FlcE.

HARRY G. WEBSTER, F CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO KELLOGG SWITCHBOARD & SUPPLY COMPANY, A CORPORATION 0F ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM.

Application led June 10, 1907, Serial Nm 378,184. Renewed October 15, 1918. Serial' No. 258,288.

-To all 'whom t 'may concern:

Be it known that I, HARRY G. WEBSTER, residing in Chicago, county of Cook, and State of Illinois, have invented new and useful Improvementsin Telephone-EX- change Systems, of which'the following is a specification.

I have illustrated my invention 1n con-` nection with a.system wherein a portion of the connections made in putting through a call fromv a calling subscribers line to a called subscribers line is effected by manuallyoperated Lswitching devices at the exchange, the -remainder of the connections being made by means of electrically operated step-by-step switching devices. An object of my invention is to provide a simple and reliable operating system wherein the advantages found in the employment of operators at the exchange are preserved, while the extensive and costly multiple spring-jack equipment of subscribers lines at each section of the switch-board is dispensed with. In this connection, the Aobject of my inventiont includes further the doing away with the complicated calling devices at the subscribers stations and the placing of a rela' tively small number of automatic 'calling vswitch mechanisms atvthe operators positions, which as far as their manual manipulation is concerntd are merely key-boards for counting out the called number. A' further object is to provide certain improved arrangements and structures ofl automatic switching means as hereafter more specific# ally pointed out in which respects my invention will be defined in the claims in Iterms applicable to purely automatic systems as'well as tothe semi-automatic system h:rein Vshown and described in detail. In accordance with my invention, I pro-` vide each operator at the exchange with a also employedv second selectors and connectors. Y l 1 u In connection with each operators cordcircuit, I further preferably provide a calling device for controlling the sets of electri- 'cal impulses to be transmitted to the selectors and connector 'used in completing the connection from the calling plug to the called subscribers line. This device may preferably be arranged in the form of a keyboard upon whichthe operator may register the number of the called subscriber, an electromagnetically controlled device being associated with the key-board for then auto-I matically transmitting impulses corresponding to the number registered by the operator. By this arrangement, the operator is not required to continue to give her attention to the call she is putting through, while the sets of impulses are being transmitted,

but may as soon as she has registered thek number, which act will consist only in counting out the called numbery by depressing suitable keys on the key-board, turn her attention to other work.

Associated with operators cord-circuits' I have provided the customary supervisory signals, one for the called line and one for the calling line, and lhave so arranged. the.

structure of 'my invention that the return to normal of the selective switches employed in a connection is effected by the removal on the part of the operator of the calling plug from vthe trunk spring-jack. This, and other. features of myinvention will be at length detailed in the following specific description.

In Fig; l, including parts l, 2 and, I have illustrated the circuits of a telephone systemxembodying my invention; in Fig.` 2,

is shown a plan View of the key-board structure before referred to; Figs. 3 and 4 are respectively side and ,fro-nt elevations of a selective `switch adapted for employment in connection with the circuits-of Fig. 1; Figs. 5 and 6l are views respectively of-'a primary Aolf-normal and secondary off-normal @switch combination, forming a part ofthe main ',switch; Fig. 7 is a detail of themain switch shaft showing the secondary pawl and the retaining dogs, and in Fi 8 is shown the arrangement of the restoring spring of the switch.

Referring first to Fig.` 1, I show at L 'and l M two'su'bstations including the usual com-I l mon battery equipment, each connected by its telephone line to the exchange and there provided with 'its' respective' linerelay 8 1,10.

controlling a signal lamp 11, a cut-off relayl 12 and an answering spring-jack comprising contacts 5, 6 and 7 Eachl line is further provided with multiple calling terminals 2, 3 and 4 located in the banks of a suitable number of connectors. As called lines, the lines of the system are grouped according to hundreds, multiple terminals 2, 3 and 1 of the lines of a hundred line group appear- ,ing in the banks of a number of connectors of which there may be ten for each group. The contact banks of the connectors may have the contact sets of the lines arranged in groups according to the tens values of the lines, and a customary Way which I have followed consists of placing each such group of contact sets upon a different level.

A connector whose circuits are illustrated at Q may comprise the Wipers 141-142-1113 adapted to be lifted step-by-step in a vertical direction to select the required group of contacts of the lines which it serves, and then rotated to select the particular contacts out of the preliminary selected group. It will be understood that the contacts 2, 3 and 4: are multipled througout the banks of the connectorsI serving the line to Which they pertain.

Assuming an exchange of ten thousand lines, there would be one hundred groups of one hundred lines to each of which groups ten connectors would be assigned, making a total ofone thousand connectors..

A second selector of which the circuit is illustrated at I), comprises the adjustable contact ;Wipers 103--104-105 adapted to engage ten levels of multiple contacts 10S- 10$108 pertaining to ten groups of connectors; "the Wipers therefore reach in all one hundred connectors assigned by tens to ten different groups of the subscribers lines. In this operation, the Wipers of the second selector are first 'adj usted vertically to select the group of multiple terminals of the desired connector group. (it being understood that the terminals of the connectors are arranged according to their hundreds values in groups of ten vat thc second selectors), whereupon the Wipers of the second selector are rotated to seek out terminals.. of an idle connectorbf the preliminary selector group.

For theten thousand line exchange, one thousand second selectors P would provide sufiicient facilities to take care of the business to be expected, and as a second selector serves a group of one thousand lines, on a basis of ten per cent trunkin one hundred second selectors would be assigned for connections to the connectors of one thousand lines. Thus the multiple terminals 106- 107-108 of the connectors wold'be multipled before the Wipers 103-104-105'of one hundred second selectors. l

The first selector of which. the circuit is illustrated at O, may include the vertically and rotarily adjustable Wipers 8687-,88, and each first selector may have access to terminals 89-90-91 of one hundred second selectors, such terminals being arranged in groups according to the thousands values of the lines served by their second selectors, vertical move-ments of wipers 86--87--88 being employed to select the group, and rotary movements being employed to select an idle second selector. The second selectors terminate as indicated at O in spring-jacks multipled to the different operators positions, each spring-jack being provided with a signal lamp 50, the arrangement being such that when a called plug g is inserted in any multiple jack, all the signal lamps of the jack and its multiples are illumined thus giving a visible busy test at the different operators positions.

The operators cord-circuit may comprise the answering plug gV in association with which is provided the supervisorysignal 18 jointly controlled by the ltip relay 16' and sleeve relay 17 in the Well known manner. Associated With the calling plug g is the calling supervisory signal 23 controlled by the polarized relay 22 in permanent bridge of the talking stands of the cord. The said polarized relay is controlled by the called-for party in a manner hereinafter to be described.

It will be understood that three parts of Fig. 1 are to be placed with part 1 to the left, the calling plug g being approached to the spring-jack o first selector O; part 2 being placed in the middle, While part 3 is placed to the right of part 2, Wipers 103--104105 being approached to the conmais 106--107-10 f e From the above it will be understood that the calling subscriber L, by removing his receiver, operates the line relay to signal the operator, who thereupon inserts into the answering jack of this line, the answering plug g. After learning the' number of the out of such group assigned for connectionl vto the thousand subscribers group designated by the first -digit of the called subscribers number.` The second set' of impulsesfcorresponding to the second digit of the called ,subscribers number is effective to cause the second selector P to pickout :a group of connectors'and then an idle switch The first set is effective to lne desired subscriber, site thereupon inserts the of such group, assigned for connection to the hundred group of subscribers designated by the second digit of the called subscribers number. Thethird set of impulses will cause a connector Q, to select the tens group of contacts of its bank among which those of the called line are included, the fourth set of contacts then causing `the connector to pick out its multiple contacts connected to the called line.

At R is an auxiliary switch for controlling the application .of ringing current to the called subscribers line, fo'ur generators G, G, G2 and .G3 being shown connected to contacts adapted for engagement by the wiper 154. The fifth set of impulses trans mitted by the calling device is effective to step the wiper 154 around to select the generator of proper frequency to ring the bell of the called subscriber, it being understood that the party line signaling system hereindisclosed may be the tuned reed system disclosed in patent to William W. Dean, No. 779,533, dated Jan. 10, 1905.

The selective switches employed are adapted for operation'responsive to a series of breaks or openings caused in the circuit vof conductor 22"L at the cord-circuit while the calling plug'g is connected to a jack, cach break in the circuit of said conductor causing a step of the selective switch, while a break in the circuit of conductor 22b of the circuit will, under similar circumstances, be effective to produce certain auxiliary circuit changes in the operations of the switches to be hereafter described. It will be noted that the conductors 22rl and 22b are normally united through the windings of polarized relay 22. The relay 24 by its armature 26 controls the circuit of conductor 22, and the said armature, when attracted, first engages the contact 25 and then causes it to leaveits normal contact, while relay 27 by its armature 29 similarly controls the circuit of`the conductor 22". These two relays are the means which I employ for transmitting the switch impulses to the selector switches, and they are in turn controlled by devices associated with the switch shown at S.

The said switch at S may comprise essentially a ratchet 36 fastened to a shaft 33 upon which are mounted the disk 36rl and the two wipers 34 and 35. The magnet 39 for driving the shaft 33, by means of the ratchet 36 and the pawl 40 mounted upon the magnets armature, is connected in circuit between battery 44a and the armature of relay 153, which armature is provided with a front contact connected to ground, and a back or normal contact connected to the offnormal switch spring 38 which normally engages a stud 37 upon the disk 36a. Theoperation of the switch S is initiated upon the cnergization 'of relay 153. which receives a current impulse to cause it to attract and then release its 'armature in the manner hereinafter described. The said armature then completes a circuit of battery 44 through magnet 39, said armature and the front contact to ground. Magnet 39'thereupon effects a thrust of pawl 40, turning ratchet 36 a step in a reverse clockwise direction whereupon spring 38 rides down over stud 37 and engages its alternate contact, whereupon when the armature of relay 153 is retracted on the cessation of the momentary impulse referred to, constantlyy rotating interrupter I comes into play and successive impulses are transmitted through magnet 39 causing ratchet 36, shaft 33, disk 36a and wipers 34-35 to be moved step-bys'tep in a rotary direction. Successive impulses will be transmitted through magnet 39 as long as contact 38 continues to engage its associated contact, which it will continue to do until a complete revolution ofdisk 36 has been effected, at which time the stud 37 will have been brought around to again engagcthe spring 38and lift it free from its contact preventing further actuation of magnet 39, and the switch S will come to a stop. Thus, whenever relay 153 is energized and (le-energized, the switch S will be operated until it has completed a revolution.

In actual practice, the arrangement of the calling device will be such as to permit of four series of ten impulses or less each, to be transmitted by the switch S with a suitable time interval between each set of impulses, and in addition to the four sets, a

fifth set of impulses for operating the party f line switch R. For the sake of simplicity in the drawing however, I have illustrated a device with lits associated connections adapted to transmit four sets of impulses, each set of five impulses or less and a fifth set of four impulses. ai', a2, a3, at* and a5 4are contact springs for the transmission of the thousands digit ofthe called number, in the arrangement shown being arranged to transmit a number of impulses corresponding to their exponents. Each spring is provided with a separate button p of which however one only is shown and that associated with the spring e5. The buttons p may bevarranged and interrelated one to another in a manner similar to that shown in patent to Michael Setter, dated September 5, 1905, No. 799,019, namely such that -when a button is depressed by an operator,

it remains depressed until the operator depresses another one, at which time the first will be automatically restored by an asso ciated spring to its normal position, in which the button shown at P is illustrated. The springs b', b2, b3, b* and b5 are the springs for transmitting the hundreds impulses of the called'subscribers number and each is provided with a button p', one only being shown, each button p being yinterrelil lated as described, for the buttons p. Similarly the springs c to c5 inclusive are the springs for transmitting the impulses of the tens digit of the called number, each being provided with 'a suitable button p2, similarly interrelated as described for the buttons p. The springs d to (Z5 inclusive are the springs for transmitting the units digit of the called number, each being provided with a button 7), interi-elated as described for the buttons y?. The springs e, e2, e and c are for transmitting the impulses to determine the frequency of the ringing current to be impressed upon the called line, and each is provided with a button fr* which buttons will be interrelated after the manner of the buttons p. The buttons p however, have associated with them respectively the springs f, f2, f3 and f4'. Then a button p4 is fully depressed by the operator, it closes its respective spring f momentarily to ground; the button being instantly released by the operator, it is raised by its associated spring to a position where it permits the springf to disengage its associated grounded Contact. The button will not however be raised sufliciently to permit its spring e, shifted when the button is depressed, to again disengage its contact. Thus supposing that the called subscriber-s number is 55554, the operator will depress the tivebuttons illustrated. The button p will cause spring a to engage its contact and remain in engagement therewith and buttons p', 792, p3 will also cause their respective springs b5, c and (Z5 to engage their associated grounded contacts and remain in engagement therewith. The spring p4 when depressed and released will cause spring f* to engage its grounded contact, and then allow it to disengage the same and will cause spring e4 to engage its grounded Contact and remain engaging the same. The buttons will of course be depressed by the operator in sequence according to the digits of the called number. Assuming that the number to be called is 55554, the operator by depressing the buttons named will cause the irst contact A associated with wiper 34 to be grounded, also the first contact B, the first contact C, the first contact D and the first contact E. Moreover, by the operation of button p, an impulse was caused to flow from ground through spring f4, relay 153 to battery 44, energizing and (le-energizing relay 153, whereon the switch S starts upon a revolution as before described.-

It may be here stated that, the teeth of ratchet 3G are so spaced with respect to the contacts of wipers 34 and that two steps of the ratchet are required to move the Wipers from one contact to the next. The first step of the ratchet brings wipers 34 and 35 to engage the first contacts A and AA respectively. Because button p is depressed,

wiper 34 finds ground on the first contact A engaged, and therefore closes a circuit from ground through the contact A and relay 152 to battery 44, operating relay 152 which is immediately locked to ground through contact 42-41, the spring 41 riding upon the periphery of disk 36a. As soon as relay 152 is energized, current flows from the grounded conductor 164 through the first contact AA, through the attracted armature of relay 152 and through relay 24 at the cord-circuit to battery 44, energizing and cle-energizing relay 24. As switch S continues in its rotation', relay 24 will be energized and de-energized each time wiper 35 engages a contact AA and, as there are five such contacts shown, each connected to the grounded conductor 164, five energizations of relay 24 will be produced and armature 2G will be attracted five times, causing conductor 22a to have its circuit opened and closed an equal number of times. It will be seen that relay 152 controls the number of impulses transmitted through relay 24, and that the said relay 152 will be energized and locked just as soon as wiper 34 engages a grounded contact A. If the button associated with say spring (L2 has been depressed, wiper 34 would not have found ground until it had reached the next to the last contact A at which time relay 152 would have become energized and locked, and wipery35 would then have begun transmitting they impulses through relay 24. Similarly, if spring a has been actuated, but one impulse would have been transmitted and the shifting of 4spring a or a* would have been effective respectively, to produce three and four energizations of relay 24. It will be understood that a device for transmitting a maximum of tenimpulses would have ten contacts A, AA, B, BB, etc.

As soon as wiper 85 passes over the last contact AA, the disk 36?1 will have been turned to such an extent that the bent portion of spring 4l will drop down into the depression SA, the said spring then disengaging contact 42 to open the locking circuit of relay 152 cle-"energizing it; the spring 41 then engages contact 43 whereby an impulse of current is caused to fiow from ground through contact 41-43, relay-27 to battery 44, energizing and de-energizing said relay, and opening the circuit ot' conductor 221 a single time. The impulse through the said relay is momentary only because with the continued travel of switch S, spring 41 passes out of the notch SA to the periphery Vof the disk, being thereby shifted back to engage the spring 42, but this has no effect upon, the relay 152, its armature being retracted. The switch S now rotates wipers 34 and 35, passing over the spaces between the sets of contacts A and B and AAand BB respectively, no effect being produced llt) upon the relays 24 and 27. This .is to allow time for the secondary ymovements of the switch that is being operated which, having by the impulses transmitted through the relay 24 been caused to select a Group, now proceeds responsive to relay 27 matically select idle contacts of the group.

As soon as wipers 34 and 35 reach their respective contacts B and BB, wiper 34 will find a ground upon its first contact B at spring b5; relay 152 is therefore again operated and locked through contact 4241, and wiper 35 moving over the contacts BB, transmits five impulses from thev grounded conductor 164 to relay 24, one impulse for each contact BB engaged by it while relay 152 is operated. If the spring b2 had been the one operated, relay 152 would not have been operated and locked until wiper 34 had reached the fourth contact B, in which case, only two actuations of relay 24 would have occurred and consequently the circuit of conductor 22a would have been opened twice only instead of five times. As'the wipers 34 and 35 advance beyond the last of their contacts B and BB, spring 41 engages the notch SB, said spring being then shifted to engage contact 43, unlocking the relay 152 and operating the relay 27 over the circuit before describe'd.

The two sets of impulses just described as transmitted were., of course, the'thousands and the hundreds digit impulse sets. When the wipers 34 and 35 reach the contact sets C and CC, the tens impulses will be transmitted in manner corresponding to those before described, the secondary impulse being immediately thereafter transmitted by spring 41 engaging the notch SC; similarly, when the wipers reach the contacts D and DD, the unit impulses will be transmitted, followed by an impulse -through relay 27 ,when spring 41 engages the notch SD, and

a similar yoperation takes place with respect to the contacts E and EE followed by an impulse through relay 27 when spring 41 engages a notch SE. l Immediatelyfollowing this engagement, the stud 37 opens the circuit of spring 38 and its contact stopping the switch S. It is thus seenthat when the operator has counted out the number of the called subscriber, the switch S proceeds to y-step, the vertical retaining pawl 162 en'- automatically transmit successive sets of current impulses for controlling. the switches, entirely independent of further attention by the operator. It will be understood however, that the employment of the impulses transmitting switch S is not limited t the circuit arrangement in which I have elected to illustrate it, namely, one in which operating relays are associated with a' lcord-circuit, which relays operate to open the conductors controlling the selectors and connectors,.but that it may be employed in various circuit relations, as to transmit imto autopulses directly to the relays or magnets of selective switches or for periodically opening predetermined numbers of times, circuits of relays or magnets of selective switches or other devices, the invention being in this respect of broad scope and capable of varying employment.

In Fig. 2 are shown the tops of a bank of buttons which may convenientl be disposed in the operators key shelfy in alignment with the pair of plugs to which the bank belongs. The numbers 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 in a vertical row indicate the number of impulses which their respective buttons. may be supposed to be capable of transmitting, while the letters a, b, c, d, and e indicate the values of the digit rows, a being the thousands, b the hundreds, 0 the tens, d the unitsand e the generator switch impulse row.

For use in connectionwith the switch circuitsshown at O, Pand Q, any preferred form" of mechanism may be employed. Inv

Figs. 3 to 8 inclusive, I show a preferred form in which the contacts are arranged in two banks, of which 160, comprising one hundred sets of contact p airs arranged in ten superposed groups of ten contact pairs, a horizontal row of pairs being a group, may include=the talking contacts of the switch. The lower bank 161, comprising one hundred single contacts arranged in corresponding groups may be the so-called private contacts. For convenience of reference,.the mechanical figures have supplied to them reference characters corresponding to those of the irst selector O. Fastened to the shaft 159,l suitably journaled to the switch frame, is the wiper :86 adapted to be adjusted by vertical movement of the shaft 159 to a position horizontal with a group of private contacts 89, and then rotated in a clock-wise direction over the contacts to engage any contact of the selected roup. The talking wipers 87 and 88 also astened to the shaft 159 move correspondingly with the wi er 86 to a corresponding located gfoup o, contact pairs, and also over the contact pairs of the group.

The vertical ratchet 155 is fastened to the' shaft, said ratchet being adapted for engage-f ment by the armature driven pawl 158 of rimary magnet PM to lift the shaft stepauxiliary switches are provided, one being a primary off-normal switch PON comprising vthe contacts 69-70 controlled by the arm 165 fastened to shaft 159. The shaft is held in its normal position, by a suitable spring 167, Fig. 8, and at such time the arm` 165 presses against the primary off-normal switch springs and holds them at normal position; with the first vertical movement of the shaft however, th arm 165 is raised free of the spring an two springs by their tension move to engage their contacts. A rotary off-normal switch is also provided comprising the springs- 67-68 controlled by the arm 166. This arm may preferably be keyed to the shaft 159 so 'asvnot to partake of the vertical movements thereof. As soon however, as the first rotary step of the shaft is made, the arm 166 is brought free of the spring 67 and the two springs are free b y their tension to move to4 their alternate positions. To restore the switch to normal, additional impulses are caused to pass through magnet SM- until on the eleventh impulse, the wipers pass beyond the right edge of the banks, Fig. 4. When this occurs, the vertically extending slot 175 in ratchet 155, shown in Fig. 7, has reached vertical i'etaining dog 162 and the shaft and wipers are free to drop to their normal level. As they reach this, rotary ratchet 1 56 is below rotary retaining dog4163 (see Fig. 3) and spring 167 comes into play to rotate. the shaft and wipers back to normal, at which times arms 165 and 166 restore switches PON and SON.

Spring case 172 fastened rigidly to shaft 159 is connected to one end of spring 167, th'e other end thereof being fastened to arm 171 at a point adjacent to shaft n159. Said arm 171 has an orifice at each end, one fittlng about shaft'159 and the other about the post 170, while arm 176 on case 172 engages arin 171 \when,the switch is at normal to the end that there may be no pressure ofyarm 171 upon post 170 while the shaft is being adjusted vertically. To provide for a similar absence of pressure when the shaft is descending to its normallevel, the spring arm 174 is carried by case 172 so positioned that on an eleventh rotary step of the shaft it slips over arm 171 to a position like the normal one of arm 176 and so relieves pressure upon post 170. As, however, the shaft completes its descent to normal level, the horizontally extending part of arm 17 impacts on piece 173, whereby arm 174 frees 'arm 171 -by being raised, and spring 167 is effective to' rotate'the shaft back to normal as described. At 155l a tooth of ratchet 155 is omitted so that after an eleventh rotary step of the shaft, further actuations of pawl 157 (which continue till the switch is restored) are ineffective to produce further rotary travel. i

The remaining features of the system of VVFig. 1 will be best understood from the fol his receiver whereupon lever 1 engaging its n alternate Contact, operates line relay 8 by current from battery 44 through said relay over a limb of the telephone lice, through hook-lever 1 and its alternate contact, returning over the other limb of the line to ground lat a back contact of cut-off relay 12, operated relay 8 attracting its armatures to display signal lamp 11 and connect battery through armature 9.with the private contacts 2 of the line at the connectors causing the line to test busy as soon as the call is initiated.V To answer, the operator inserts the plug g into the answering jack of the' line, current then flowing from battery 44 through relay 17, contact 15-5, cut-off relay 12 to ground, which relay Yattracts its armatures to de-energize relay 8, whereby signal lamp 11 becomes inert. Armature 9 in falling back connects battery from contact 5 to multiple contacts 2 so that they may retain their busy potential. Relay 17 was operated and would cause the display of signal 18 were not relay 16 energized by current from ground to contact 13A-6 over the subscribers line, returning through contact 7-14 to battery through impedance coil 19. The operator having learned the number of the called subscriber, inserts the calling plug g" in a multiple jack of a first selector suchas 0 whose signal 50 is not displayed. On the insertion of the plug, con' tact 49 engages its associated contact, closing circuit from ground through all the lamps 50 of that switch O at the different operators positions in parallel to battery 44, displaying them as a busy indication. Upon the insertion of the plug, current flows from the negative side of battery 44h, through primary relay PR atV switch O, contact 53,

Vcontact 47 30, contact 25 through the windings of polarized relay 22, contact 28, contive pole of battery 45a, the batteries 45a and 44b being arranged in series. rIhis flow of current is in a direction to operate the armature of relay22 to close its contact, display-` ing signal lamp 23 which remains displayed until the called subscriber answers the call. Relays PR and SR being now operated, their armatures close a circut through release control relay RCR to battery 44, armature 63 being now attracted to place an operating ground upon the normal contacts of the now attracted armatures 58 and 61, while i larmature 64 is attracted, placing a shbrt cir- -about the ywinding of the release relay '45, and on the retraction of armature 26,

the first energizing circuit of relays PR and SR and 22 is re-established before the circuit holding the relays 22 and SR energized is broken. Each time vrelay PR is de-energized, its armatures are retracted, armature 58 on each retraction transmitting an im- .pulse from Aground through armature 63,

contact 67, primary magnet PM to battery 44, the said magnet PM vlifting the wipers 86-87-88 to a position horizontal with their fifth level of contacts, forming terminals of second selectorsY of the fifth thousand subscribers group. With the first upward step of the wipers, primary off-normal springs 69 and 70 are shifted, 69 to operatively connect battery 44 to the normal contact of armature 64, and 70 to operatively connect the busy relay BR tothe normal contact of springs 681.l v.

The single impulse transmitted by switch F S to operate relay 27, after the fifth impulse hasleen transmitted through/ relay 24, attracted and released the armature of 27 whereby' circuit is momentarily broken by the opening of conductor 22h through secondary relay SR of switch O, although relays 22 and PR are not affected since. an alternate circuit is completed for them from the negative/side of battery 44b through contact'28-29, contact 32-46 to ground, before the first energizing circuit is broken and on the retraction of armature 29, the initial energizing circuit is recompleted before the substitute one is broken. The armatures of relay SR are momentarily retracted, armature 61 causing an impulse to iow from ground through armature63, ar-

mature 61, switchrcontacts 68, 70, busy relay BR to battery operating the said relay, whose attracted armature 73 closes a `circuit from generator through secondary mag net SM to ground, the said magnet thereon causing a rotary Vstep of the wipers 86-87- 88 to engage the first-multiple contacts 89 90-91 of the selected group. If these contacts pertain .toy'a busy switch ,P, contact 489- will be grounded over a circuitextending from a multiple thereofthrougha Wiper -86 of a' first selector which has already oclcupied the switch P,A through' itsnormal contact and alternate contact 64 to ground, inwhich case the busy relay BR i of the switch of Fig. 1 will be locked up by current from the grounded contact 89, wiper 86, alternate contact 72, normal contact 76, contact 70, relay BR to battery, and its armature 73 will continue attracted, successive vsimilar locking circuits being established until wiper 86 in its rotation` lreaches an ungrounded contact 89, whereupon the locking circuit for relay BR will be broken, the relay (le-energized and its armatures retracted. Obviously as long as relay BR remained locked, successive impulses flowed through magnets SM advancing the switch step-by-step until relay BR became de-energized when the opening of contact 73 brought the switch to rest. While switch O is moving over multiple contacts of busy second. selectors, wipers 87-88 are on open circuit at attracted armatures 71- 74. With the first rotary movement of the switch before described, the secondary offnormal switch springs 67-68 were shifted to disconnect magnet PM and relay BR from armatures 58 and 61 respectively, in order that a clear circuit may exist from said armatures through wiper 87 and 88 to the circuits of the selected second selector P as soon as relay BR was de-energized.

The `contacts,92-93d94 may be provided as the tenth contact set of the group, in which case there will be but nine selectors P available. The contact 94 is not multipled and wipers 86 will therefore always find it ungrounded, the switch stopping on contacts 9- 92-93 if the preceding nine contact sets are already busy. Should this matically receive a busy signal from interrupter I as relay BB is alternately energized and de-energized under the influence of interrupter I2, the busy current flowing from the interrupter I through the right armature of relay BB, contact 92*87, contact 58, condenser 59, contacts 53, 47-30, 25, condenser l82, contactv 13-6 over the line and through the receiver, returning over contacts 7-14, 28, 31e-48, 54, condenser' 62, alternate contact 61, contact 74, `contact 88- 93 to ground giving the calling subscriber the busy signal whereon he will replace his receiver to display signal 1,8, due to the consequent de-energization of relay 16, whereon the operator will withdraw the plugs, returning thejapparatus. to normal as heretofore described.

The switch O having been thus vertically and vrotarily vadjusted 'to engage the idle second selector P, the next set of five impulses'representing the hundreds digit transmitted through relay 24 effect 'five delenergizations of relay PR and ghe transmission,

PM to battery, magnet PM lifting.' the switch wipers to select the roup of contact sets, terminals of the fth group of connectors, which connectors pertain tothe 5500 group of subscribers. On the energization of relay 27 by an impulse following the five through relay 24, -relay SR is de energized momentar1ly and an impulse transmitted from ground through contacts 63, 61, 74, 88--91, 96, 98, of the primary off-normal Switch PON', l(shifted on .the first vertical step of the switch) through busy relay BR', which is energized to close circuit through secondary magnet SM' -whereby the secondIselector P i's caused to automatically pick out the contacts 10G- 107-108`ip`ertaining to the first idle connector of Afthegroup, in a manner similar to that in twhich the first selector picked out the idle second selectors contacts, the locking circuitforrelay BR being extended through alternate contact 100, while the talking wipers 104-105 are on open circuit at attracted armatures 912-102, while the switch was rotating. |The shifting of contact 97 connected'multiplecontacts 89 with the winding of'release relay RR `of the second selector; It will be observed that at this time'theJ-low resistance circuit to ground at' the attracted larmature 64 of release control relayRCR at second selector O is extendedithrou'gh normal contact 72 and wiper 80', to multip e contact 89, retaining the second selector P busy, and also to normal contact 100 and wiper 103 to multiple contact 106 of the-connector, retaining that switch busy, while the release relays RR and RR of the first y,selector and second selector are shunted fb 'athisl low resistance circuit so thatjit :is .impossible for the said relays to be vactuated should other switches whose relays BRwere attracted, pass their wipers over, the multiplesofontacts engaged by the private wipers 86.`and 103 of the two i switches O and P. lln the `heretofore proposed systems in which a private wiper has been used for both selecting and releasingv purposes, it has beencustomary to depend upon a proportioning of the resistances of.

the busy relays andthe release relays to prevent premature actuations of the latter, what might be called the busy ground at the private wiper of a switch being usually traced through the trunk release relay, and my present system is arranged to obviate `the necessity of marginal proportioni'ng of I relays hitherto employed.

' The third set of impulsesv representing the tens digits' efl the called number trans! mitted throughv relay 24, effect five de-energizations of relay PR andfthe transmission of five impulses from ground through arma'- ture tal-contact 58., 71, rrr- 90, 99, 10i- 107, back? contact 111, `primary magnet PM2 to battery 45;", actuating the magnet PM2 five tacts of the one hundred lines served by the,

connector including the lines numbered 5551 to 5559 inclusive, followed by the line No. 55550,V zero being represented by ten impulses in automatic systems. A succeedin; ,1r energization of nrelay 27 produced by switch S following the five energizations described, of the relay 24 energizes and de-energizes the secondary relay SR, acurrent impulse flowing from ground through contact 63, 61, 74, 88-91, 102, 105-108, through contact 109 (primary olf-normal, PON2, switch springs 109 and 110 having been shifted by the first vertical step of the connector) through locking relayA LR to battery 45h, actuating the locking relay which is locked to ground at the VVspring 110 via armature 112 and its contact. The attraction of armature 113, of relayfHIqiRf-.by closing circuit from'battery 44d thr'ugh'contact 113, normal contact 147, normal contact 117, to ground through test relay TR, energizes the said relay in order that the same may be operated while wipers 142, 143 are wiping contacts 3, 4 of lines not wanted and when the test circuit is completed as hereafterv described. Armature 114 completes a break in the circuit of release relay RR2, while i tol battery 45".

When switch S, by operating relay 24, causes the five unit digit impulses to be transmitted from ground through armature 63, they willfpass through secondary mag.- net SM2 which will be effective to rotate the shaft and wipers 141-142-143 to engage the fifth multiple contacts 2-344 of the group horizontal with which the wipers have been adjusted by the tens impulses. rlhe secondary impulse fgllowing the five will traverse the before traced path through wiper 105, thence to contact 108, closed con-. tact 109, the now shifted secondary offnormal contact SON2 through locking relay LR tol battery 45b whereby' relay 'LR' will be energized and locked through contact 1 31--130 to ground at shifted primary offnormal, PON2` contact 110` Armature 132 being attracted, the circuit before described lfrom contact 107 is shifted from secondary magnet SM2 to extend through alternate contact 132, contact 144, through rotating magnet M to battery` 45" so that the fifth Contact 144, magnet tvbettery, actuating magnet M four times which is effective to step 'l the wiper 154 four rotary steps to engage the contact of generator G3.

It may be stated that magnet M is a driving magnet for4 the Wiper 154,. while magnet RM is a release magnet, the former actuating a driving ratchet, the latter being adapted to withdraw a retaining pawl from the ratchet of the wiper to render the restoring spring effective to restore the switch to normal in the wellknown manner.

` four The secondary impulse following the impulses operating )the generator switch R will pass through contacts 108, 109, secondary off-normal spring SONZ, olff normal springJONtshiftedlwith the firstv step of the switch R- through normal contact' 146, locking relay LR2 to battery 45T', relay LR2 locking itself through contact 145-146to ground at 110. The attraction of armature 134.0n thel energization of reinitiated a cal-l that has not been "answered,

attracted armature 9 will have connected battery 44r1 to contact 2 and its multiples. I f thejcall has been answered by the inser? tionof a plug in the answering jack, battery through relay 17 of the answering cord, contact 15-5 and normal ncontact 9, has

VYbeen applied to multiple contact-.2. If the V*line o f M is busy as a called line, a battery connection to contact 2 and its multiples will have been extended from the circuits of another connector already applied to a multiple of contact 2' from battery- 44d, to the right, then upward through normal contact 134 and wiper 141 of such other connector. consequently found' at the multiple contaet2 yof the called line engaged by mwiper 1 41L of switch Q will develop into-a current eirculating -through alternate Contact 134 of relay TR of switch Q, contact 148-147 contact 117, relay TR to ground, causing the relay to continue energized ,whereby busyfmachine It is operatively associated.

with the calling subscribers line, giving the7 subscriber theA customarybusy signal overV aicircuit extending through contact 149, at-

tracted armature 136, condenser 129, normal contact 125, contacts`108-105, 91"-88, 48

31514-7, over the line -limbsof subscriber L and'. through his` receiver, returning, througlr eontact 6-13 to ground through y relay' 16 `and PR. The calling subscriber In each of these cases the potential hearing the signal will replace his receiver, de-energizing relay 16 to display lamp 18, and the operator observing the two lamps 13 and 2 3 both displayed, will remove the plugs from the spring-jacks restoring the line circuit of L to normal, and also're storing the switches O, P and Q, in the manner hereafter described. A

Assuming however, that the called -line is idle, there willbe no battery connection to the multiple contacts 2 as will be clearly seen from an inspection of the line circuit of M in its normal or idle condition, shown in F-ig. 1. In such case, contact 2 is con# nected to ground only throu h cut-ofi:` re lay 12,and wiper 141 being a so connected to ground only through the winding of test relay TR since armature 148 is attracted, the test relay TR necessarily becomes inert and its armatures are retracted, whereof 133 and 137 close contacts in the talking' conductors, armature' 136 immediately dissociates busy machine I* from the calling vline so that he does -not receive the busy signal, while armature 134 connects the active side of .battery 44d with wiper 141 and multiple contact 2 to render the called line busy, whereby also cut-oil' relay 12 is operated to disconnect line relayv8 from the called line.- Armature 135 now operatively connects interrupter Is through normal contact 124, contact 135, closed contact 150, 4

through control relay CR to battery and as' interrupter I3 rotates, relay CR is alternately energized and de-energized,` with each energization connecting the vgenerator G3 through wiper` 154, alternate contact 139, to ywiper 143 and contact 4 of the called line,I the current passing out over the line through vcondenser and call-bell at the sub.- station notifying the'called subscriber that f `his attention is desired, .the currsnt returning'through contact 3-142 and through alternate contact 138 to ground, the current being of frequency to ring the bell of subscriber' M only, the bells of M', M2 and M3 responding to vGetal 'andG2 respectively;

The called subscriber answering the'l call removes his receiver and as soon as relay CR is de-energized, current -lows from battery 44d through impedance 140, contact 13.3, normal 'contact 138, contact 142-13" over the line'through the now raised hook lever at the subs-tation,l through receiver and transmitter, returning over the: other line limb, contact 4--143, normal contacts 139,v 137 ,relay 126 to. ground. This flow of current supplies talking battery tothe called subscriber and is also effective by the actuation of armature 127 of relay 126to energize locking relay LRs, which, by armature 123 locks itself to ground at 110.v Armar.

from relay CR SO that the relay continues .ture 124' now disconnects. interrupter I inert and ringing currentv is henceforth ex- *,130

- cluded from the called line.

Armatures 120 and 125 complete normally open contacts in the talking circuit, armature 121 places an additional ground upon the private contact 106 because armature 122 in engaging its alternate contact has removed control of release relay RR2 from the operators plug switch connection, the connecf tor from now on being controlled as to its release solely by the called subscriber, and if it were not for the ground at 121, the operator might, in withdrawing the plug, before the called subscriber replaced his receiver, disconnect the second selector from the connector, and another second selector wiping contact 106 would stop in connection with connector Q, which would not do as the connector would be still in use being connected to the line of M. Circuit is now closed from battery 44d through the impedance 140, contact 120, 107-104, 90-87, alternate contact 58, pole changing relay 51 to battery 44c whereby relay 51 is operated and reverses the connections of batteries 45 and 44b to the conductors 22 and 22h, whereby reversed current passes through the windings of polarized relay 22 and its armature is shifted to disengage its contact whereby lamp 23 is put out andthe operator knows that the subscribers are in conversation. The two subscribers are now in conversation, the talking circuit being .traced through the exchange over the heavily marked conductors, condensers 82 and '59 being interposed in one side of the talking circuit, while condensers 83 and 62 are in the other side of the talking circuit, battery being supplied to the calling line through the inductances of relays 16 and 17, and to the called line through the inductances o f relayv 126 and coil ,140.

At the conclusion of conversation, the subscribers replace their receivers, the subscriber L in so doing de-energizes relay 16 and lamp 18 is displayed in the usual manner. When subscriber M replaces his r'e-. ceiver, circuit is opened through relay 126 and its armature 128 falls back to engage,

its contact, whereby circuit is closed from battery 45b through said contact, alternate contact 122, armature 114, release relay RR2 to ground, which relay now attracts its armature 116 to complete a locking circuit for itself, armature 115 to energize release I'nagnet RM at the generator switch R which magnet withdraws a retaining pawl and allows wiper 154 to be snapped back to normal by its associated spring, at which time off-normal spring ON* will be restored and locking relay LR2 de-energized, while armature 118 of release relay RR2 completes a circuit from battery 44d` through Contact 118-117 and test relay TR to energize the said relay to open the circuits of line wipers 142 and 143 at contacts 133-137 S0 that they may be disconnected while the connector is being rotated over contacts of not wanted lines to the restoring rotary posl- -tion under the influence of secondary magnet SM2 whose circuit is now closed by the attraction of armature 119, from battery 45b through interrupter I2 to ground. As soon as the eleventh step in a rotary direction is made, the shaft and wipers drop and are thereupon ,restored rotarily to normal,

opening the primary off-normal, PON2, and

from contact 106, while retracted armature' 120 opens the circuit before traced through relay 140 at Q and relay 5l at O, whereby relay 51 is de-energized and its armatures retracted whereupon the connections of batteries 44" and 45a to conductors 22a and 22b are restored to their initial condition and current through lpolarized relay 22 is again reversed whereon its armature closes the circuit of supervisory signal 23 and the operator knowing that disconnection is desired, both signals being now displayed, withdraws plugs g and On the withdrawal of g, relay`22 is o course deenergized, and relays PR and SR are deenergized now for the first time since the plug was inserted in the jack of switch O. v

The de-energizations allow the simultaneous retractions of armatures 57 and 60, and release control relay RCR has its'armatures retracted of which 64 completes a circuit from battery 44c over conductor 80, shiftedv primary off-normal contact 69, contact 64, the` current then dividing, a portion flowing through release relay RR, whose armature 75 immediately locks the relay through spring 69; the remainder of the current flowing through contacts 72, 86-89, contact 97, release relay RR to ground, the said relay looking `itself by current from battery 44c'over conductor 84, contact 97 to ground. Armature 76 of relay RR closes a circuit throughA busy relay` BR via contact 70 whereby the relay is operated to place wipers 87-88 on open circuit at Contact 71-74,vwhile relay BR at switch P is operated by the attraction `of the right armature of relay RR. Current impulses now flow through magnets SM and SM of the two switches O and P, through the attractl pletely restored, effective to de-energize the operated relays of the switches which ar then at normal. j

It should be observed that I have associated the call counter 66 with the first selector O, which counter may comprise the usual counting train controlled by the magnet operated responsive l,to armature 56 f pole changing relay 51, when the called subscriber answers the call whereby the number of completed connections may be registered.

It will be understood that when the ope erator withdraws the plug, the switchv contact 49 of the spring-jack of switch O disengages its contact and the signal lamps 50 ceaseA to be displayed.

Let it be assumed that the called subscriber fails to answer the call, or that the busy signal was extended to the calling subscriber and that under these conditions, the

operator withdraws the plug g from the jack. In such case the circuit operating relay RR before described'would ind a conductive branchvia contact 100, contact 10S- 106, normal contact 122, (because relay LR3 is only actuated in case the called sub scriber answers), through contact 114, andA release relay RRZl to ground.' In suchcase,

the three relaysRR, RR and RR2 would be' energized and locked, and the respective switches vwith which they are` associated would be returned to normal in the Ina-nner the organization of a system according to.

my invention including several exchanges, the operators would have accessible to their link-clrcuits, multiple terminals grouped together for each exchange and connected to trunks leading to first selectors O of each exchange of the system. On receiving the calling subscribers order, the operator would cause her link-,circuit to be connected to `multiple terminals of an idle trunk leading to the distant exchange where the called for subscribers line had its terminals. .I prefer to have the conductor 77 a common return conductor for the trunks leading to where the operator. lis employed yas differ` a particular exchange connected to ground at the distant exchange rather than to a ground conductor local to the exchange ences of earth potential are to be expected at different localities included in a system, and such differences would tend to interfere -with the proper operation of the Switching are produced.

cuit a potential equal to that ofground at the exchange to which the trunks lead, the

potential varying for the different exof the connection terminals of a set of trunks to the potential of the distant ground `may be effected by making the conductor 77 In operation, the two operating relays PRl and SR are connected in a bridge 1n.- cluding battery across the impulse transmitting .conductors 22a and 22", which conductors have a second bridge, in the lcircuit `shown including the windings of relay 22,

while the impulse transmitting springs 26 and 29V control contacts in the said conductors located intermediate of the two bridges.- .It-will be remembered that whenl vretraction of spring `26, the original energizing circuit for the two relays PR and SR, having the full voltage of the serially `disposed batteries 44h and 45a, is 're-.established for energizing anew the relay PR.

With a number of actuations of spring 26,

the above would be repeated, and it isclear that the re-energizations of relay PR are effected over the metalliccircuit of'th'esiinf-n pulse transmitting conductors 22a and 22.

When spring 29 is actuated, complementary switching operations for de-energlzing relay SR and holding relay PR energized In the automatic telephone systems before referred to, a common return or local lground is used for energizing the operating relays, the local grounds being at points distant from the exchange where the relays are. 'I-o care for variations in earth potential at such ground connections, or the rcsistance of the common return, a central battery of relatively high voltage is customarily employed, as the relays must be quickly energized when the conductors, with lwhich they are Vrespectively connected, are applied to the ground or common return. In my. present structure, the ground or third conductor being employed only to ,hold an alreadyoperated relay operated, it

is apparent that chances of trouble from the' ylao use of thc ground or common return are very' materially reduced, as it is well known that after a relay is once operated and its armatures are attracted, but a very small per cent of the current originally required for its initial operation is necessary to cause its continued operation'.

Having described my invention in a speciic manner with reference to one embodiment thereof, it will bel understood that it is not my intention to be limited tothe specific structures illustrated. It is for instance, well known that selectivej switches may be employed for ythe purpose of associating the calling subscribers lines with operators link-circuits, and it is not my purpose to limit my invention to the specific plug and jack arrangements shown in certain portions of the specific embodiment of my invention.b It will also be understood that the various sources of electrical energy which I have shown at different places in the circuit diagram of Fig. l, need not be so many individual sources but where identical symbols are indicated, the various` sources may be, and preferably are, a single source. Of course where distant eX- changes are comprised in a system,each eX- change is preferably provided with its individual battery supply. Similarly, the various interrupters marked I with different exponents may be a single interrupter. Ot' course for the furnishing of ther different frequencies of current for ringing the tuned bells, different generating devices are preferably employed. I

I-Iaving thus described my invention, what I claim as new and desire to secure by Letters Patent of the UUnited States,

1. A telephone system including subscribers lines, operator controlled selective switches for interconnecting said lines, an operators impulse transmitter including an electromagnetically adjusted traveling contact member serving to transmit current impulses to operate said switches, and a second electromagnetically adjusted traveling member for said impulse transmitter for controlling the number of impulses transmitted by said first member.

2.. A telephone system including subscribers lines, Vselective switches for interconne'cting said lines, an operators impulse transmitter provided with a traveling contact member serving 'to transmit impulses to Aoperate said switches, a second traveling l member for said impulse transmitter, a

switching device for determining the number of impulses transmitted by said first member, `a source of current and a circuit including said second `member and said source of current for operating said switch-, ing device.

3. A telephone system'including telephone lines and selectivel switches for making con nection therewith, controlling 4mechanism for determining the operation of said switches including an impulse transmitter, an electromagnet for operatively associating when energized, and dissociating when der-energized, said transmitter with and from said switches, a traveling contact member for operating said magnet, an automatic switch for effecting travel of said member, means controlled by said switch at fixed points in its Voperation for deenergizing said magnet, and manually manipulated switching` means for controlling the circuit lof said traveling member to control the time of energization of said magnet.

4. A telephone system including telephone lines and selective switches for making connection therewith, a circuit making-andbreaking device for controlling said switches, an automatic switch, a plurality of sets of stationary contacts for said automatic switch, one set Jfor each set of circuit makesand-breaks to be produced by said device, a plurality of sets of switch contacts, one for each set of stationary contacts, each stationary contact having its corresponding switch contact, manual means for operating selected switch contact-s, one of each set to alter the circuits of the corresponding stationary contacts, a travelling member for said automatic switch, and means controlled thereby for operatively associating said device with said selective switches as often as, and when, said member engages a stationary contact whose circuit is altered.

5p. A telephone system including telephone lines and selective switches for making connection therewith, a circuit making-andbreaking device for controlling said switches, an automat@I switch, a plurality of sets of stationary contacts for said automatic switch, one set for each set of circuit makesand-breaks to be produced by said device, a plurality of sets of switch contacts, one for each set of stationary contacts, each stationary contact having its corresponding switch contact, manual m ns for operating selected switch contacts, one of each set to, alter the circuits of the corresponding stationary contacts, a travelling member for said automatic switch, means controlled thereby for opera. tively associating said device with said selective switches as often as, and when, said member engages a'stationary contact whose circuit is altered, and mechanism automatically eli'ective at xed points in the travel of l neet-ion therewith, a circuit making-andbreaking device for controlling said switches,

an automatic switch, a plurality of sets of.

station-ary contacts for said automatic switch,

one set for each 'set of circuit makes-andbreaks to be produced by said device, a plurality of sets of switch contacts, one for each .set of stationary contacts, each stationary contact having its correspondingswitch contact, manual means for operating selected switch contacts, one of each set to alter the circuits of the corresponding stationary connection therewith, a circuit making-andbreaking device for controlling said switches, an automatic switch, a plurality of sets oi'l stationary contacts .for said automatic switch, one set for each set of circuit makes-and-breaks to be'produced by said device, a plurality of sets of switch contacts, one for each set of stationary contacts, each stationary contact having its corresponding switch contact, manual means fonoperating selected switch contacts, one of each set to alter the circuits of the corresponding stationary contacts, a travelling member for said automatic switch, means controlled therebyfor operatively associating said device with said selective switches as often as, and when, said member engages a stationary, contact whose circuit is altered, mechanism automatically effective at fixed points in the travel of said member to operatively' dissociate said device from said; selective switches, a manually operated device for initiating travel of said automatic switch, and means for stopping said switch when said member reaches a normal point.`

8. A telephone system including telephone lines and selective switches for making connection therewith, a circuit making-andbreakmg device'y for controlling sald switches, and electromagnet controlling lswitching mechanism for operatively associating and dissociating said device with and from said switches, an automatic switch, manually operated means for initiating travel thereof, the subsequent travel of said switch to a normal point being automatically controlled, manually controlled switching means for producing energizations of said magnet to operatively associate said device with said selective switches at selected points in the operation of said automatic switch, and switching means automatically controlled by said automatic switch for de-energizing said ma net at fixed points in the operation of sai automatic switch to dis- -sociate said device from said selective switches. l,

9. A telephone system including subscribers lines, selective switches for use in interconnecting said lines, an operators impulse transmitter for operating said switches, a. traveling Contact member for said transmitter, stationary contacts for en agement by said member to co-operate t erewith in controlling said switches, a second v travelling member for said impulse transmitter provided with stationary contacts, manually operated switching devices for said transmitter for controlling the circuits of said last contacts, a ,relay for co-operating with said' second member, a contact therefor, amanually operated device, and a. circuit controlled by said last device including said relay contact for controlling the operative relation of said first member with said switches.

l0. A telephone system including subscribers lines, selective switches for use in interconnecting said lines, an operators impulse transmitter located at the exchange for operating said switches, a traveling contact member for said transmitter, stationary contacts for engagement thereby one for each number to be transmitted by said transmitter, manually operated keys for operatively altering the electrical condition of said contacts, la controlling relay for effectively completing connection between said transmitter and said switches, and means for opera-ting said relay over a circuit including said traveling member and the first contact engaged thereby whose circuit is altered.

11. A telephone system including subscribers lines, selective switches for use in interconnecting said lines, an ,operator-s impulse transmitter for operating said switches, a traveling contact member for said impulse transmitter, stationary contacts for engagement thereby one for each number to be transmitted by said transmitter, manually operated buttons for altering the electrical condition of said contacts, a controlling relay for electivelyV associating said transmitter with said switches, means for operating the said relay over a circuit including said traveling member and the first cont-act engaged thereby whose electrical condition is altered, and electromagneticallyI driven means for effecting travel of said member.

12. A telephone system including sub-- trical condition of said contacts, a controlling relay for eii'ectively associating said transmitter with said switches, means for operating thesaid relay over a circuit including said traveling member and the firstP contact engaged thereby whose electrical condition is altered, electrmagnetically \driven means for effecting travel of said scribers lines, selective switches for connecting with called lines, an impulse transmitter for transmitting directive currents to said switches, a key-board for said ltransmitter having manually actuated switch members, one for each thousands digit, one for each hundreds digit, etc., and a traveling device for said transmitter common to and controlled by said switch members only and effective to produce sets of current impulses corresponding in numbers to the values of the actuated members.

14. A telephone system including subscribers lines, selective switches for use in completing connections to called lines, an impulse transmitter for transmitting a plurality of sets of directive impulses to said switches, manually operated key members and switching means controlled thereby, one for each digit of each impulse set to be transmitted, and mechanism for said transmitter controlled by said key members and switching means only and controlling the numbers of impulses of said sets according to the values of the actuated members.

15. A telephone system including telephone lines, an electromagnetically controlled connector for connecting to a called line responsive to directive current impulses, Contact wipers for said connector including a talking wiper and a test wiper, a test relay controlling a contact in the circuit of said talking wiper, means for holding said relay energized while said talking wiper is engaging lines not wanted whereby said wiper is on open circuit, and a switch for shifting said relay to connection with said test wiper when said talking wiper is engaging the vwanted line to render the continued energization of said relay dependent upon the idle or busy condition of said line.

. 16. A telephone system including telephone lines, an electromagnetically controlled connector for `connecting to a called line responsive to directive current impulses, contact wipers for said connector including a talking Wiper and a test wiper, a test relay controlling a contact in the circuit of said talking wiper, means for holding said relay energized while said talking wiper is engaging lines not wanted whereby said wiper is on open circuit, test contacts for said lines for engagement by said test wiper, means for altering the normal electrical conditions of said contacts to render them busy, and a switch for'shifting said relay to connection with said test wiper when said talking wiper is engaging the wanted line.

17. A telephone system including telephone lines, an electromagnetieally controlled connector for connecting to a called line responsive to directive current impulses, contact wipers for said connector including a talking wiper and a test wiper, a test relay controlling a cont-act in the circuit of said talking wiper, means for holding said relay energized while said talking wiper is 'engaging lines not wanted whereby said wiper is on open circuit, test contacts for said lines for engagement by said test wiper, and a switch for rendering said test relay sensitive to the idle or busy condition of the test contact of the wanted line on connection made therewith.

18. A telephone system including telephone lines, an electromagnetically controlled connector for connecting to a called line responsive to directive current impulses, contact wipers for said connector including a talking wiper and a test wiper, a test relay controlling a contact in the circuit of said talking wiper, means for holding said relay energized while said talking wiper is engaging lines not wanted whereby said wiper is on open circuit, test contacts for said lines for engagement by said test wiper, a switch for rendering said test relay sensitive to the idle or busy condition of the test contact of the wanted line on connection made therewith, and mechanism controlled by said test relay for extending a busy signal, or completing a portion of a .talking circuit according to the idle or busy condition of said contact.

19. A telephone system including telephone lines, a connector for connecting directly with a called line, auxiliary selective switches for successive operation in establishing connection from a calling line tosaid connector, restoring electromagnets, one for each of said selective switches, a release control circuit extending from switch to switch, a central source of current, branch connections from said control circuit, one

'for each magnet extending through said 20. A telephone system including I'telephone lines, a connector for connecting difor each of said selective switches, a release` rectly, with a called line, auxiliary selective switches for successive operation in establishing connection' from a callingline to said connector, restoring 'electromagnets, one

control circuit extending from switch to switch, a central source of current, branch connections from sald control clrcult, one for each magnet extending through said mag-4 nets to one pole of said source, an additional branch connection from said circuit to said one pole, short-circuiting said magnets while saidswitches are in use, a release control relay and mechanism therefor controlling the ,continuity of said additional branch, and means for controlling the operativev condition :of said relay when disconi lishing connection from a calling line to said connector, restoring electromagnets, one

for each of said selective switches, a release control circuit extending from switch to switch, a central source of current, branch connections-from sald control clrcuit, one

jor each magnet extending through said magnets to one pole of said source, an additional branch connection from said circuit to said one pole, short-circuiting said,mag nets while said switches are in use, a release control relay and mechanism therefor controlling the continuity of said additional branch, means for controlling the operative' condition of said relay when disconnection 1s desired for opening said additional branch to rferer said magnets operable, and

apparatus or connecting said source of currentto 4said control circuit to operate said Vmagnets while said additional branch is open when disconnection is desired.

22. A telephone system including telephone lines, a connector for connecting directly with a called line, auxiliary selective switches lfor'successive operation inestab- ,lishing connectiony yfrom a calling line to said connector, restoring' electromagn'ets,

one for each of said selective switches,` a

release-control circuit extending from switch to switch, a central source of current, .branch connections lfrom, saidv control circuit, one for each 'magnet extending through said magnets to one pole of said' source, an additional branch-connection from. said circuit to said v.one pole, short-circuiting said magnets.:whileh'saidfswitches are ,iin use,

. means for controllingwthe continuityfof said 'i f additional'f'connection to render/said magnets operable, andfapparatus lfor connecting said source of current to said control circuit to'operate said magnets while said additional branch is open when disconnection is desired. v

23. A telephone system includingJ subscribers lines, connector switches for connecting directly to a called line in establishing a connection, auxiliary selective switches for operation in completing connection from a calling line to said connector, an operating relay for transmitting successive sets of directive impulses to' the selective switches andthe connector switch in establishing a connection, a second operating relay for controlling the circuits of said switches, electromagnets'for restoring said switches to normal, one for each switch, a release control relay jointly controlled by said operating relays, a release control circuit extending @from switch to switch, a central source of current, branch connections from said circuit through said lectromagnets to one side of said source,'and a low-resistance branch from said circuit to said one side of said source, said branch being controlled as to its continuity b said release control relay whereby said e ectromagnets areshort-circuited while their operation is notvrequired. 24e. A telephone system ,'including sub-.- 'scribers lines, fconnector switches orconnecting Vdirectly to a called line in establishing a connection, auxiliary selective switches for operation in completing connection from a calling line to said connector, an operating relay fortransmitting succes-y sive sets of directive impulses to the selective switchesand the connector switch in establishing a connection, a second operating relay lfor controlling `the lcircuits of said switches,electromagnets for restoring said switches tonormal, one for each switch, at release controll relay jointly controlled by 'said operating relays, a release control circuit extending from switch to switch,4 a 110 vcentral source of current, branch connections from said circuit through said electromagv nets to one side of vsaid source, a low-resistance Ibranch. from said circuit `to said one side of said source, said branch being con- 115i trolled as, to its continuity by .said release .control relay whereby said electromagnets i are short-circuited while thelr, opration is -prising a plurality of signaling conductors ,130

carrying current for selectively signaling the various stations of a poly-station line and a contact member for selecting the desired conductor, a locking relay for said connector with means for operating the-same,

' tending from substations to said exchanges,

trunk lines extending from said'rstmentioned exchange to said other exchanges, grounded sources of current at said other exchanges having their ungrounded terminals connected to the trunk lines of their respective exchanges, relays included in the connection between the ungrounded battery terminal and the trunklines terminals of said trunk lines at saidV first mentioned exchange, link-circuits for connection to said terminals in establishing desired connect-ions, means associated with the terminals of said trunks for impressing upon a terminal of the linkcircuit while in connection with a trunk, an electrical potential corresponding to the electrical potential of the grounded terminal of the source of current at the particular exchange to which the trunk leads, means. at

said link circuit for impressing isaid corresponding electrical potential to other terminals of the trunk to operate said relays, and automatic switches controlled by said relays for extending said trunk circuits.

27. A telephone system including an exchange, subscribers lines terminating at said exchange, operators7 link-circuits and means for interchangeably connecting them with calling lines, a distant exchange, trunk circuits extending from said first exchange to said distant exchange and there provided with connection devices Jfor connecting to called lines, multiple terminals for said trunk circuits at said first exchange, the multiple terminals of each trunk including multiple contacts connected to a conductor individual to said trunk and extending to saiddistant exchange, an additional contact included in each terminal of each trunk, a conductor connecting the additional contacts of the terminals of a plurality of trunks, a source of current at the distant exchange, a connection extending from said conductor to the distant exchange and there connected to one pole of said source, a con- 'y nection device for an operators link-circuit for establishing connection to a terminal of atrunk, said device including a switch contact for connecting to each contact of said terminal, a connection from said individual conductor to the opposite pole of said source, andan electromagnet forsaid linkcircuit adapted lto be bridged across said lirst-mentioned contact and said additional contact.

28. A telephone system including an exchange, subscribers lines terminating at said exchange, operators link-circuits and means for interchangeably connecting them with calling lines, a distant exchange, trunk-circuits extending from said first exchange to said-distant exchange and there provided with connection devices for connecting fto called lines, lmultiple terminals for said trunk-circuits at said first exchange, the multiple terminals of each trunl including multiple contacts connected to a conductor individual to said trunk and extending to said distant exchange, an additional contact included in each terminal of each trunk, a conductor connecting the additional contacts of the terminals of a plurality of trunks, a source of current at the distant exchange, a connection extending from said conductor to the distant exchange and there connected to one poleof said source, a connection device for an operators link-circuit for establishing connection to a terminal of a trunk, said device including a switch contact for connecing to each contact of said terminal, a third contact for each multiple terminaha busy or test circuit controlled thereby, means effective on connection made with a terminal to alter the circuit of said third contact torender the trunk busy, a connection from said individual conductor to the opposite pole of said source, and an electromagnet forsaid link-circuit adapted to be bridged `across said first-mentioned contact and said additional contact. y

29. A telephone system including an eX- changehsubscribers lines terminating at said exchange, operators link-circuits and means for interchangeably connecting them with calling lines, a distant exchange, trunk-circuits extending from said first exchange to said distant exchange and there provided with connection devices for connecting to called lines, multipleiterminals for said trunk-circuits at said first exchange, the multiple terminals of eachA vice including a switch contact for connecting to each contact of said terminal, a con? nection from' said individual conductor to 

